Obstructive sleep apnea syndrome is characterized by symptomatic recurrent upper airway obstructions during sleep that may result in serious physiologic abnormalities, medical risks, and quality of life deficits. It occurs in 2 - 4% of adults and is a target disorder for Healthy People 2010. Providing continuous positive airway pressure (CPAP) represents first-line therapy. Surgical treatment may serve as an adjunct to CPAP or as a second line definitive therapy, but surgical effectiveness data are lacking. The principal investigator's long-term goal is to evaluate rigorously surgical treatment of the nasal, oral, hypopharyngeal, and laryngeal airways for sleep apnea as an independent investigator. For the period of this award, he proposes to develop sophisticated surgical outcomes research skills through a program of didactics, conferences, focused clinical activity in the Sleep Disorders Center, and hands-on research with the guidance of expert advisors. This research proposal focuses on the role of nasal obstruction, and its surgical correction, as a means of improving clinically important outcomes of CPAP therapy. The specific aims are to: 1. Determine whether nasal obstruction influences CPAP treatment outcomes above and beyond other behavioral and biomedical factors in a prospective inception cohort study. 2. Conduct a pilot trial to examine whether surgical treatment for nasal obstruction improves CPAP outcomes. This single-site pilot trial will provide the principal investigator with clinical trials experience as well as data on logistical, feasibility, and measurement issues for a definitive trial. Future independent investigations of other surgically correctible anatomic abnormalities associated with sleep apnea will follow the model of this proposed research plan.